1. Field
The present application relates to gas turbines, and more particularly to a system and method to minimize flow induced vibration in a gas turbine exhaust system.
2. Description of the Related Art
The turbine exhaust cylinder and the turbine exhaust manifold are coaxial gas turbine casing components connected together establishing a fluid flow path for the gas turbine exhaust. The fluid flow path includes an inner flow path and an outer flow path defined by an inner diameter delimiting an outer cylindrical surface of the inner flow path and an outer diameter delimiting an inner cylindrical surface of the outer flow path, respectively. Tangential struts are arranged within the fluid flow path and serve several purposes such as supporting the flow path and providing lubrication for the turbine and rotor bearing. At certain conditions, the exhaust flow around the tangential struts can cause vibrations of the inner and outer diameter of the turbine exhaust cylinder and the turbine exhaust manifold due to vortex shedding. Vortex shedding is an unsteady flow phenomenon typically caused by high incidence on the tangential struts. It may cause large oscillations in flowpath pressures that force the flowpath structure to vibrate or even resonate strongly. These vibrations are a potential contributor to damage occurring on the flow path of the turbine exhaust manifold and the turbine exhaust cylinder. This damage to the casing components may require replacement or repair.